Mitch, amazing advice. I would be DD all winter, but I would also be taking amazing care of it and washing the undercarriage at least once a week to remove the salt. I would also be completely re-painting it before the first snow, not just a typical paint shop paint, but removing every single panel and tending to any rust that has started to build on each panel individually.
I am considering coating the undercarriage in spots of high rust vulnerability with rhino liner or something similar. I have heard this is a great rust/salt protectant, and can be easily removed to check if rust has started to build under it, well relatively easily removed.
However you are making me see that 5k might be to much for this truck. I have yet to find one in better condition however, at least cosmetically. I have yet to test drive it.